Add copyright headers to all the new files.

sdr_rtlsdr.h

@@ -1,8 +1,26 @@
+// Part of dump1090, a Mode S message decoder for RTLSDR devices.
+//
+// sdr_rtlsdr.h: rtlsdr dongle support (header)
+//
+// Copyright (c) 2016-2017 Oliver Jowett <oliver@mutability.co.uk>
+// Copyright (c) 2017 FlightAware LLC
+//
+// This file is free software: you may copy, redistribute and/or modify it  
+// under the terms of the GNU General Public License as published by the
+// Free Software Foundation, either version 2 of the License, or (at your  
+// option) any later version.  
+//
+// This file is distributed in the hope that it will be useful, but  
+// WITHOUT ANY WARRANTY; without even the implied warranty of  
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License  
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 #ifndef SDR_RTLSDR_H
 #define SDR_RTLSDR_H
 
-// Support for DVB-T dongles in SDR mode via librtlsdr
-
 void rtlsdrInitConfig();
 void rtlsdrShowHelp();
 bool rtlsdrOpen();